Incremental hybrid welding systems and methods

ABSTRACT

Embodiments of a welding power supply include an engine adapted to drive a generator to produce a first power and a energy storage device adapted to discharge energy to produce a second power. The welding power supply also includes control circuitry adapted to detect a commanded output. The control circuitry is adapted to meet the commanded output by controlling access to power from the energy storage device to produce the second power when the commanded output is below a first predetermined load level. The control circuitry is further adapted to meet the commanded output by controlling access to power from the engine and the energy storage device to produce the first power and the second power when the commanded output is above a second predetermined load level.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Patent Application of U.S.Non-Provisional application Ser. No. 14/066,305, entitled “IncrementalHybrid Welding Systems and Methods”, filed Oct. 29, 2013, now U.S. Pat.No. 10,092,971 and U.S. Non-Provisional application Ser. No. 12/894,038,filed Sep. 29, 2010, entitled “Incremental Hybrid Welding Systems andMethods” now U.S. Pat. No. 8,569,652, which are Non-Provisional PatentApplications of U.S. Provisional Patent Application No. 61/261,960entitled “Incremental Hybrid”, filed Nov. 17, 2009, all of which areherein incorporated by reference in their entirety.

BACKGROUND

The invention relates generally to welding systems, and, moreparticularly, to hybrid welding systems.

Welding is a process that has become increasingly ubiquitous in variousindustries and applications. As such, a variety of welding applications,such as construction and shipbuilding, may require welding devices thatare portable and can easily be transported to a remote welding location.Accordingly, in some cases, it is often desirable for such weldingdevices to be operable as standalone units remote from a power grid orother primary power source. Therefore, a variety of welding systemsutilizing alternate power sources, such as batteries, have beendeveloped. Furthermore, during a welding operation, some weld loaddemands may be small (e.g., below 150 amps), and to meet such small loaddemands, the engine-generator unit is activated. However, activation ofthe engine-generator to meet such small load demands is ofteninefficient. Accordingly, there exists a need for hybrid welding systemsthat overcome such drawbacks.

BRIEF DESCRIPTION

In an exemplary embodiment, a welding system includes an engine adaptedto drive a generator to produce a first power output, wherein the engineis rated below approximately 25 horsepower. The welding system furtherincludes a battery adapted to discharge energy to produce a second poweroutput and a charger coupled to the battery and to the engine andadapted to receive power from the engine and to charge the battery withthe received power. The welding system also includes a controlleradapted to control access to power from the battery to produce thesecond power output when a commanded output is less than or equal to afirst threshold, to activate the engine to produce the first poweroutput when the commanded output is between the first threshold and asecond threshold, and to activate both the battery to produce the secondpower output and the engine to produce the first power output when thecommanded output is greater than or equal to the second threshold.

In another embodiment, a welding power supply includes an engine adaptedto drive a generator to produce a first power and a battery adapted todischarge energy to produce a second power. The welding power supplyalso includes control circuitry adapted to detect a commanded output andto meet the commanded output by controlling access to power from thebattery to produce the second power when the commanded output is below afirst predetermined load level and to meet the commanded output bycontrolling the engine-generator and the battery to produce the firstpower and the second power when the commanded output is above a secondpredetermined load level.

In another embodiment, a method of controlling a hybrid welding systemincludes determining a commanded output of the hybrid welding system,activating an engine-generator unit to produce a first power outputsubstantially equal to the commanded output when the commanded outputlevel is below the first threshold, and activating the battery and theengine-generator unit to produce a combined power output substantiallyequal to the commanded output level when the commanded output level isgreater than or equal to the first threshold.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a block diagram illustrating exemplary components of anincremental hybrid welding power supply in accordance with aspects ofthe present invention;

FIG. 2 is an exemplary method of controlling the incremental hybridpower supply of FIG. 1 in accordance with aspects of the presentinvention;

FIG. 3 illustrates exemplary control logic that may be utilized by thecontroller of the power supply of FIG. 1 to meet an auxiliary loaddemand;

FIG. 4 is a graph illustrating an exemplary load detected at an outputterminal of the incremental hybrid power supply of FIG. 1; and

FIG. 5 is a graph illustrating an exemplary detected load, an exemplarybattery output, and an exemplary engine-generator output in accordancewith aspects of the present invention.

DETAILED DESCRIPTION

As described in detail below, embodiments of an incremental hybridwelding system and methods of controlling such a system are provided.Embodiments of the hybrid welding system may be adapted to provideoutput power to meet small load requirements (e.g., less thanapproximately 150 amps) commanded by an operator without activation ofan engine-generator unit disposed therein. For example, the hybridwelding system may include an energy storage device (e.g., a battery, acapacitor, etc.) coupled to an associated converter and capable ofmeeting small commanded output requirements. Indeed, althoughembodiments of the present invention are described below in the contextof a battery based system, additional embodiments may include any of avariety of suitable energy storage devices, such as capacitors, fuelcells, etc. Furthermore, embodiments of the disclosed hybrid weldingsystems may include engines with ratings below approximately 22horsepower (hp), approximately 23 hp, approximately 24 hp, orapproximately 25 hp but may still be capable of producing output powerto meet large load commands (e.g., above approximately 250 amps) bycombining output power from both one or more batteries and theengine-generator unit. For further example, in some embodiments,embodiments of the hybrid welding systems may include engines withratings between approximately 12 hp and approximately 16 hp, which mayoperate up to approximately 180 amps without energy storage device powerand up to between approximately 250 amps and approximately 300 amps withenergy storage device supplemental power. Furthermore, the incrementalhybrid welding system may include a charger configured to recharge theone or more batteries with output power from the engine-generator unitand a controller adapted to control the access to power from the one ormore batteries and the engine-generator unit.

In the embodiments described herein, for example in the embodiment ofFIG. 1, the hybrid welding systems are shown in the context of a weldingsystem (e.g., a metal inert gas (MIG) welding system) including awelding torch. However, as used herein, the term “welding operation”refers to conventional welding processes (e.g., MIG welding) as well ascutting operations and gouging operations. Similarly, as used herein,the term “weld power output” may refer to a power output from a weldingprocess, a cutting process or a gouging process. Indeed, embodiments ofthe disclosed hybrid welding systems may be provide power in anincremental manner for a welding process, a cutting process, or anyother suitable welding operation.

Turning now to the drawings, FIG. 1 illustrates an exemplary hybridwelding power supply 10 adapted to incrementally initiate one or more ofa variety of power outputs. To this end, the illustrated hybrid powersupply 10 includes a controller 12, an engine-generator unit 14including an engine 16 and a generator 18, a charger 20, a battery 22, aconverter 24, and a weld power converter 26. The hybrid power supply 10includes output terminals coupling to an auxiliary output 28, a weldingoutput 30 illustrated as a welding torch, and a ground 32.

In the illustrated embodiment, the engine-generator unit 14 and thebattery 22 are each coupled to a separate power converter, weld powerconverter 26 and converter 24, respectively. However, in furtherembodiments, a single power converter may be configured to receive powerfrom both the engine-generator unit 14 and the battery 22 and to convertsuch incoming power to one or more appropriate power outputs. Stillfurther, the illustrated embodiment shows the engine-generator unit 14,the weld power converter 26, the battery 22, and the converter 24 housedin a single mechanical enclosure. However, in further embodiments, suchcomponents may be coupled together in mechanical enclosures in any of avariety of suitable ways. For example, in one embodiment, theengine-generator unit 14 may be coupled with the weld power converter 26in one enclosure, and the battery 22 and the converter 24 may be housedin another mechanical enclosure. In such an embodiment, the separatemechanical enclosures may be coupled via cabling through the weldingenvironment.

During operation, the hybrid welding power supply 10 is configured tomeet the commanded power levels of the welding operation in anincremental manner, as described in detail below. Such commanded poweroutput levels may be commanded based on one or more of amperage,voltage, wire type, wire feed speed, stick electrode diameter, and soforth. As such, the engine 16 is configured to drive the generator 18 toproduce power, which may be utilized to provide the auxiliary output 28,to charge the battery 22 via charger 20, and/or to power the weld outputvia the weld power converter 26. In some embodiments, the engine 16 mayhave a rating of below approximately 75 hp, below approximately 55 hp,below approximately 45 hp, below approximately 35 hp, belowapproximately 25 hp, below approximately 15 hp, or below approximately 5hp. For example, for high power welding operations (e.g., cutting orgouging operations) the engine may have a rating of up to approximately75 hp such that the engine is configured to meet the high power demandsof the welding operation.

Further, the battery 22 is configured to discharge to produce power,which may be routed to the welding torch 30 via converter 24 and/or tocutting and/or gouging torches and/or auxiliary power throughappropriate converters, such as to a synthetic auxiliary output. Thecontroller 12 is configured to receive input (e.g., sensor feedback,manual inputs, etc.) regarding the process operation and to selectivelyaccess power from the engine-generator unit 14 and the battery 22 toproduce power as needed. For example, such an embodiment may beapplicable in instances of low frequency, high peak power demands inwhich the engine-generator output is supplemented by the energy storagedevice output. In such embodiments, the energy storage device may berecharged during instances of lower power demands from either theengine-generator unit or from another power source when theengine-generator unit is OFF.

For instance, in one embodiment, the controller 12 may be adapted toaccess power from the battery 22 to produce a power output to meet acommanded output level (e.g., the desired output as specified by anoperator via a control on the welder) when the commanded output level isbelow a first predetermined threshold (e.g., 150 amps) and to activatethe engine-generator unit 14 to produce power only when the commandedoutput exceeds the predetermined threshold (e.g., 150 amps). In suchembodiments, when the commanded output exceeds the predeterminedthreshold, no power may be drawn from the battery and theengine-generator unit 14 may power not only the commanded load but alsothe recharging of the battery 22. Still further, the controller mayaccess power from both the battery 22 and the engine-generator unit 14to meet the commanded output when the commanded output exceeds a secondthreshold (e.g., 300 amps). As such, the controller 12 may be adapted toimplement an incremental power access method to ensure that thecommanded outputs of the welding operation are met in an efficientmanner. Furthermore, such an incremental approach to control of thehybrid welding system may allow for the engine to be small, for example,rated for less than approximately 25 horsepower, while maintaining theability to handle large loads (e.g., above approximately 300 amps).

FIG. 2 illustrates an incremental control method 34 that may be utilizedby the controller 12 to control operation of the hybrid welding powersupply 10 of FIG. 1. The method includes the step of identifying thatthe welding system has been turned ON (block 36), for example, byidentifying that an operator has switched the power switch to the ONconfiguration on the control panel of the welding power supply. Themethod 34 further includes checking for the presence of an auxiliaryload (block 38). In the illustrated embodiment, if an auxiliary load isdetected, the engine-generator unit is activated to meet the auxiliaryload demand and any other commanded weld outputs that may be present(block 40). Subsequently, the controller continues to monitor theauxiliary load demand, the commanded weld outputs, and the batterycharge level to determine when to activate and deactivate theengine-generator unit as the welding operation proceeds (block 42).However, it should be noted that although in this embodiment, theengine-generator is activated upon detection of an auxiliary loaddemand, in other embodiments, the controller may meet the auxiliarydemand without activation of the engine-generator unit. For example, asynthetic auxiliary output may be provided, for example, via access topower from the battery, as described in detail below.

The illustrated method 34 further includes checking if a presentcommanded weld output is less than or equal to a first threshold (block44). For example, in one embodiment, the controller may check if thecommanded weld output is less than 150 amps, although in otherembodiments the first threshold may be any predetermined level suitablefor the given application. If the commanded output is less than or equalto the first threshold, power is accessed from the battery 22 and theconverter 24 to meet the initial commanded output (block 46). That is,in such instances, the engine-generator unit may remain OFF while thebattery is utilized to meet the commanded output. Such a feature mayreduce the amount of fuel consumed to power the welding operation ascompared to non-hybrid systems that run the engine-generator unitcontinuously to meet all commanded outputs and to traditional hybridsystems that allow the engine to idle while the battery provides power.Subsequently, the controller 12 continues to monitor the variouscommanded outputs present at one or more output terminals of the powersupply as well as the battery charge level (block 42) to determinefurther access to power from the battery output and the engine-generatoroutput.

If the load is not less than or equal to the first threshold, thecontroller checks if the load is between the first threshold and asecond threshold (block 48). For example, in one embodiment, thecontroller may check if the load is between approximately 150 amps andapproximately 300 amps. If the load is within the threshold values forthe given application, the controller activates the engine-generatorunit to output power to meet the demand (block 50) and to charge thebattery (block 52) if the battery is below a full charge level.Subsequently, the controller monitors for further commanded outputs andthe battery charge level (block 42).

Alternatively, in another embodiment, the controller may check if thecommanded power output level is below the second threshold and, if so,the controller may activate the engine-generator unit to meet thecommanded level without activation of the battery. The controller maythen further check if the commanded output level is greater than orequal to the second threshold and, if so, the battery may be activatedto supplement the engine-generator output. That is, in some embodiments,the engine-generator may be utilized to meet small commanded outputlevels (e.g., below a preset threshold), and the battery may beactivated to produce a power output that is coupled with theengine-generator output when the preset threshold is exceeded.

In the illustrated embodiment, if the load is not within the firstthreshold and the second threshold, the controller checks if the load isgreater than or equal to the second threshold (block 54). If so, thecontroller controls access to power from the engine-generator unit 14 aswell as the battery 22 coupled to the converter 24 to meet the commandedoutput (block 56). That is, if the necessary power output exceeds thatwhich the engine-generator unit 14 or the battery 22 is capable ofexclusively outputting, the power outputs of both units are coupledtogether to provide the appropriate output. Such outputs may be coupledin any of a variety of suitable ways (e.g., supplement a constantengine-generator output with a battery output, supplement a constantbattery output with engine-generator support, etc.), as described indetail below. If the load is not greater than or equal to the secondthreshold, the controller checks if the batteries are fully charge(block 55). If the batteries are not fully charged, the controllerutilizes the charger to charge the batteries (block 52). If thebatteries are fully charged, the controller again checks for thepresence of an auxiliary load (block 38) as before.

FIG. 3 illustrates alternate auxiliary control logic 58 that may beemployed to meet an auxiliary load demand. The method 58 includeschecking for detection of an auxiliary load (block 60). If an auxiliaryload is not detected, the controller proceeds to check for the presenceand/or level of a weld load (block 62) and controls the engine-generatorand battery as appropriate to meet the detected weld load, as before. Ifan auxiliary load is detected, the method 58 includes checking if thebattery is fully charge (block 64). If so, the controller controlsaccess to power from the battery to provide a synthetic auxiliary poweroutput to meet the commanded output (block 66) and then continues tomonitor the auxiliary load, the weld power load, and the battery chargelevel (block 68).

If the battery is not fully charged, the controller checks if thebattery is at least partially charged (block 70). If so, the controllerdetermines whether the battery charge level is enough to meet thedesired auxiliary output and utilizes either the battery output or thebattery output combined with an engine-generator output to provide theappropriate level of synthetic auxiliary output (block 72). As before,the controller then monitors for further loads and the battery chargelevel (block 68). If the battery is not partially charged, thecontroller activates the engine-generator to provide the appropriatelevel of auxiliary power (block 74) and additional output power torecharge the depleted battery (block 76). Again, the controller monitorsthe appropriate welding process parameters to determine further controlof the hybrid welding power supply (block 68).

FIG. 4 is a graph 78 illustrating an exemplary load detected at anoutput terminal of the incremental hybrid power supply of FIG. 1.Specifically, the graph 78 includes an amperage axis 80 and a time axis82. The time axis 82 includes a zero time point 84, a first time point86, a second time point 88, a third time point 90, and a fourth timepoint 92. The graph 78 includes an exemplary load plot 94 illustratingan exemplary weld demand over a welding interval. The load plot 94includes a first portion 96, a second portion 98, and a third portion100.

In the illustrated embodiment, the commanded output begins atapproximately 75 amps at initial time 84, thus prompting the controllerto initiate output from the battery 22. Accordingly, during the intervalfrom initial time 84 to the first time 86, the battery output satisfiesthe load requirement indicated by portion 96 of the load plot 94, andthe engine-generator unit remains OFF, thus conserving fuel. At thefirst time 86, a break in welding occurs, and the controller mayactivate the engine-generator unit to recharge the battery. At thesecond time 88, the battery again outputs power to meet the commandedoutput and the engine-generator unit remains OFF. Between the secondtime 88 and the third time 90, the load plot 94 reaches 150 amps duringportion 98 before another break in welding occurs at the third time 90.In the illustrated embodiment, 150 amps is a threshold level beyondwhich the engine-generator unit is activated to meet further commandedoutputs. Accordingly, at the third time, when a break in welding occurs,the engine-generator unit is powered ON.

The engine-generator unit recharges the battery between the third time90 and the fourth time 92 and remains ON to meet the commanded outputduring portion 100 of the plot. Additionally, after the fourth time 92,the battery remains OFF and recharges from the engine-generator output.In such a way, in some embodiments, the controller may shift frombattery provided power to engine-generator provided power during one ormore breaks in the welding process. Additionally, in some embodiments,during non-welding periods, the engine-generator may be turned OFF, thusconserving fuel. At the initiation of welding after the non-weldingperiod, the controller may meet the initial commanded output withbattery power output until the engine-generator power is once againneeded.

FIG. 5 is a graph 102 illustrating exemplary operation of the hybridpower supply of FIG. 1. Specifically, the graph 102 includes an amperageaxis 104 and a time axis 106. The time axis 106 includes a first time108, a second time 110, a third time 112, a fourth time 114, a fifthtime 116, a sixth time 118, a seventh time 120, an eighth time 122, anda ninth time 124. The graph 102 includes a detected load plot 126, abattery output plot 128, and an engine-generator output plot 130.

As illustrated, the graph 102 begins with the detected load atapproximately 70 amps and the battery output also at approximately 70amps to meet the load requirements, as shown in portion 132 of the graph102. Between the first time 108 and the second time 110, the detectedload increases and the battery output also increases to accommodate theincreased commanded output. The battery continues to meet the commandedoutput between the second time 110 and the third time 112, as shown inportion 136 of the graph 102. At the fourth time 114, the illustrateddemand reaches a critical point, 150 amps, thus triggering activation ofthe engine-generator output. In the illustrated embodiment, theengine-generator output increases to contribute power to meet the 150amp demand while the battery output decreases between the fourth time114 and the fifth time 116, as shown by portions 142 and 138 of thegraph 102.

In this embodiment, the engine-generator output is maintained at aconstant power output (e.g., approximately 130 amps) from the fifth time116 until the commanded output again falls below 150 amps, as shown byportion 144 of the graph. That is, embodiments of the presentlydisclosed hybrid welding systems may provide for the engine-generatoroutput to be maintained at a constant level. In such embodiments, thebattery output power may fluctuate to ensure that the commanded outputis properly met. For example, the battery power output is maintained atapproximately 20 amps, as shown by portion 140, while theengine-generator output is maintained at 130 amps to meet the 150 ampcommanded output, as shown by portion 146. For further example, as thecommanded output increases during portion 148, the battery demand isincreased in portion 150 to meet the difference between the powersupplied by the engine-generator and the desired load. Similarly, thebattery output provided in portion 154 makes up the difference betweenthe 130 amps supplied by the engine-generator and the desired demandshown in portion 152. Once again, as the demand of the load increases inportion 156 to 250 amps in portion 160, the battery output increases inportion 158 to a new output level in portion 162. As such, theengine-generator output may be maintained at a constant level while thecommanded output fluctuates, and the battery supplies additional power.

While only certain features of the invention have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the invention.

1. A welding system, comprising: an engine configured to drive agenerator to produce engine power output, wherein the engine is ratedbelow approximately 25 horsepower; an energy storage device configuredto provide storage device power output; and a controller configured to:control production of welding power output by conversion of a storagedevice output and engine power output based upon a plurality of stepwisethresholds of commanded welding power; command welding power output tobe produced from the storage device power output via a first powerconverter in response to the commanded welding power being below a firstthreshold of the plurality of stepwise thresholds; command welding poweroutput to be produced from the engine power output via a second powerconverter in response to the commanded welding power exceeding the firstthreshold of the plurality of stepwise thresholds; and command weldingpower output to be produced from both the storage device power outputand the engine power output in response to the commanded welding powerexceeding a second threshold of the plurality of stepwise thresholds. 2.The welding system of claim 1, wherein the first threshold of theplurality of stepwise thresholds is equal to approximately 150 amps, andthe second threshold of the plurality of stepwise thresholds is equal toapproximately 300 amps.
 3. The welding system of claim 1, wherein thefirst power converter is coupled to the energy storage device to convertthe storage device power output to the welding power output.
 4. Thewelding system of claim 1, wherein the second power converter is coupledto the engine to convert the engine power output to at least one of theweld power output and an auxiliary power output.
 5. The welding systemof claim 1, wherein the controller is configured to command conversionof only storage device power output to produce the welding power outputupon start up of the welding system and to allow a delay period toelapse before accessing engine power output from the engine.
 6. Thewelding system of claim 1, wherein the controller is configured toaccess engine power output from the engine when a pause in the weldingprocess is detected.
 7. The welding system of claim 1, furthercomprising a charger coupled to the energy storage device and to thegenerator and configured to receive the engine power output from thegenerator and to charge the energy storage device with the receivedengine power output.
 8. The welding system of claim 7, wherein thecharger is configured to charge the energy storage device when thecommanded welding power is between the first threshold and the secondthreshold of the plurality of stepwise thresholds.
 9. The welding systemof claim 1, wherein the controller is configured to deactivate theengine to prevent the generation of the engine power output duringnon-welding periods.
 10. The welding system of claim 1, wherein theengine is further configured to provide engine power output for anauxiliary power output when an auxiliary load is detected.
 11. A weldingsystem, comprising: a first power converter configured to convert anengine power output from an engine that is configured to drive agenerator to produce the engine power output, wherein the engine israted below approximately 25 horsepower; a second power converterconfigured to convert a storage device power output from an energystorage device that is configured to provide the storage device poweroutput; and a controller configured to: command welding power output tobe produced from the engine power output via the first power converterin response to the commanded welding power exceeding a first thresholdof a plurality of stepwise thresholds; command welding power output tobe produced from the storage device power output via the second powerconverter in response to the commanded welding power being below thefirst threshold of the plurality of stepwise thresholds; and commandwelding power output to be produced from both the storage device poweroutput and the engine power output from the first and second powerconverters, respectively, in response to the commanded welding powerexceeding a second threshold of the plurality of stepwise thresholds.12. The welding system of claim 11, wherein the controller is furtherconfigured to control an auxiliary power output by conversion of one ofthe storage device output or the engine power output from the first orsecond power converters, respectively, based upon a plurality ofstepwise thresholds of commanded welding power.
 13. The welding systemof claim 12, wherein the controller is further configured to control theenergy storage device to discharge to produce the auxiliary poweroutput.
 14. The welding system of claim 11, wherein the first thresholdof the plurality of stepwise thresholds is equal to approximately 150amps, and the second threshold of the plurality of stepwise thresholdsis equal to approximately 300 amps.
 15. The welding system of claim 11,further comprising a charger coupled to the energy storage device and tothe generator and configured to receive the engine power output from thegenerator and to charge the energy storage device with the receivedengine power output.
 16. The welding system of claim 11, wherein thecontroller is further configured to control access to the storage devicepower output from the energy storage device and control the engine poweroutput from the engine and production of welding power output inresponse to the plurality of stepwise thresholds.
 17. A welding system,comprising: an engine configured to drive a generator to produce anengine power output, wherein the engine is rated below approximately 25horsepower; an energy storage device configured to provide a storagedevice power output; a controller configured to: control access to thestorage device power output from the energy storage device and an enginepower output from the engine; control production of welding power outputand auxiliary power output by conversion of the storage device outputand engine power output based upon a plurality of stepwise thresholds ofcommanded welding power; command welding power output and auxiliarypower output to be produced from the storage device power output via afirst power converter in response to the commanded welding power beingbelow a first threshold of the plurality of stepwise thresholds; andcommand welding power output to be produced from both the storage devicepower output and the engine power output in response to a the commandedwelding power exceeding a second threshold of the plurality of stepwisethresholds.
 18. The welding system of claim 17, wherein the firstthreshold of the plurality of stepwise thresholds is equal toapproximately 150 amps, and the second threshold of the plurality ofstepwise thresholds is equal to approximately 300 amps.
 19. The weldingsystem of claim 17, further comprising a charger coupled to the energystorage device and to the engine and configured to receive the enginepower output from the engine and to charge the energy storage devicewith the received engine power output.
 20. The welding system of claim17, wherein the controller is further configured to activate anddeactivate the engine to access the engine power output and to chargethe energy storage device in response to the plurality of stepwisethresholds.